Variable pressure fluid drive mechanism



May 3, 1960 J. ZUBATY VARIABLE PRESSURE FLUID DRIVE MECHANISM INVENTOR.dZwgp/zZa qy I! AT TORNEY Corporation, Detroit, Mich., a corporation ofDelaware Application September 16,1957, SerlalNo. 684,193; '3 Claims.'(Cl. 123-140 The invention relates to a fluid drive mechanism and moreparticularly to a mechanismof the Wobble plate type as used in fluidpumps. The drive and the controls therefor may be used with a pump ofthe type disclosed in my application Serial No. 633,456, entitledVariable Pressure Fluid Pump, and filed January 10, 1957.

The fluid drive includes an oscillating member whichimparts reciprocablemotion to pump plungers which operate to pump fluid at a desiredpressure and volume. It is often desirable to vary the deliverycharacteristics of such pumps in accordance with the load impressed onassociated mechanisms such as internal combustion engines. A pumpembodying theinvention has the pump actuating ring interconnected with adiaphragm responsive toenginevacuum so that sponse to the changes in theengine vacuum automatically adjust the stroke of the pump, therebyadjusting the delivery characteristics of the pump. A pump embodying theinvention is sensitive to load on the engine since centrifugal forceacting on the actuating ring and the vacuum caused by the action of aventuri tube at the engine air intake tend to balance each other. 7During rotation, the oscillating member will tend to occupy a positionnormal to the axis of rotation due to centrifugal force. The degree ofthis tendency is proportional to the square of the speed of the driveshaft. The angle of tilt of the oscillating member is controlled byvacuum imposed by a venturi tube used on the engine intake. Thedepression tendency of the vacuum sensitive diaphragm is proportional tothe square of the air mass flow. These two tendencies will be balancedand pump output depending on load without interference of speed willresult.

In the drawing:

The figure illustrates a pump embodying the invention and having partsin section.

The pump illustrated includes a housing 10 with which a a web 12 isintegrally formed. A hearing hub 14 is located centrally within web 12.Bearing 16 is received within hub 14 and provides a rotatable mount endand locating point for the end of drive shaft 18. A second bearing 20 ismounted on the other end of drive shaft 18 and is located in the bearingcap and seal 22. Cap 22 is, secured to a pump cover 24. Several stackedplates which may be separated by gaskets are positioned intermediatepump cover 24 and housing 10. These plates include a plunger guide plate26, a pressure chamber plate 28, and a valve plate 30. Pump cover 24 maybe provided with an inwardly extending sleeve 32 on which plates 26, 28,and 30 are piloted. The valve, passage, and chamber arrangement may besimilar to that shown in the above identified application. The pressurechambers 27 may contain the piston springs 29 and be connected with theinlet 21 through inlet annulus 33 and inlet valves 35. Outlet valves 37connect the chambers 27 with outlet annulus 39 and the outlet 41.

The pump diaphragm 34 is positioned intermediate plates 26 and 28 and isused both as a pump diaphragm and a gasket. Plunger guide plate 26 hasplunger cylinmovement of the diaphragmxin rely spaced from that shaft.

ders 36 formed therein in which pump plunger pistons 38 are reciprocablyreceived. These pistons engage dia-- phragm 34 at their outer ends and,when reciprocated,

cause the diaphragm to flex, thereby imparting pumpingaction to thediaphragm. Plunger pistons 38 may be integrally formed with plunger arms40 which terminate at their ends opposite the pistons in rounded ends42.. Sockets 44 are formed within actuating ring 46 and the ends 42 ofthe plunger arms 40 are received in the sockets- Actuating ring 46 ispreferably mounted on the outerrace of bearing 48. The inner race ofthis bearing is secured to hub 50 of oscillating member 52. Hub 50extends circumferentially about drive shaft 18 and is radial-- Actuatingring 46 may be: tilted relative to the axis of drive shaft 18 bypivotal. movement of oscillating member 52. Oscillating mem-- ber 52 isrotatably driven from drive shaft 18 through. drive pin 54 and drivingmember 56. Oscillating member 52 is pivotally attached to driving member56 by hinge: 58. The axis of hinge 58 provides the pivot point for os--cillating member 52 and actuating ring 46. Actuating ring 46 may beprevented from rotating with respect tohousing 10 by pin 64 whichextends downwardly from web 12 and engages ring 46 in recess 66.

An initial manual adjustment of the oscillating member 52 may beobtained by threading tapered adjusting.

cillatingmember 52. The tapered end of screw 62 may I contact bevelsurface 60 which is formed on one side of driving member 56 adjacentscrew 62. When the screw 62 is moved inwardly, the minimum tilt angleobtainable between oscillating member 52 and driving member 56 isincreased.

The pump is preferably controlled during engine operation by vacuumsensed at a venturi throat in the engine air intake system. A typicalsystem of this type is shown in application Serial No. 591,889, filedJune 18, 1956, in the name of John Dolza and assigned to the commonassignee. A vacuum sensitive diaphragm 70 is provided for this purpose.Cover plate 72 may be suitably secured to pump housing 10 so that web 12and the cover plate form a space divided by diaphragm 70 to defineatmospheric chamber 74 and vacuum chamber 76. Vacuum chamber 76 isconnected with the engine air intake venturi throat 77 throughappropriate conduits 79 connected to vacuum inlet 78. Spring 80 may bemounted between web 12 and diaphragm 70 to resist movement of thediaphragm when vacuum is increased within chamber 76 and to return thediaphragm to its neutral position when the vacuum approaches atmosphericpressure.

Control arm 82 may be rigidly attached to diaphragm '70 and extend in agenerally perpendicular direction from the diaphragm through an aperture84 formed in web 12. A bellows seal 86 may be secured in aperture 84 topermit longitudinal movement of arm 82 while effectively sealing vacuumchamber 76 from the interior of the pump. End 88 of control arm 82 maybe threaded into or otherwise attached to actuating ring 46. Whendiaphragm 70 is moved under the influence of increased vacuum in chamber76, arm 82 is moved in a direction generally parallel to drive shaft 18and actuating ring 46 is pivoted about hinge 58. Since the engine airintake venturi throat vacuum is a function of the second power of engineair mass flow and the centrifugal forces acting on members 52 and 56 area function of the second power of engine speed, these forces tend tobalance each other, thereby making the pump sensitive to engine load.Since the speed of drive shaft 18 is directly proportional to enginespeed, the centrifugal forces acting on members 52 and 56 are alsosensitive to speed of that shaft.

Patented May3, 1960 a What is claimed is: 1. Ina fiuid pump of thewobble plate type, a housing, a drive shaft rotatably mounted in saidhousing, internal ea. n e. me ns d i n sa sh an a l:

latable mernber s filtd tq said, energ s rot'ati' with, fm eanspermitting angular movement of said oscil seams latable merriberrelative tothe axis of said shaft, a wobble plate actuating membersecured for oscillatory mov ement with said osc illatable memberrelative totthe axis'of said shaft, and differential pressure. means ioradjusting the angular relationshipof said member relative to said shaft,said dilferential pressure means being sensitive 'to the secpistonsdisposed,concentrically, about saidrdrive shaftv and nd power of the airmass flow ofsaid engine means, said oscillatable member. when rotatinghavinga centrifug'al force component sensitive to the second power .ofthe speed of said drive shaft and opposingsaid differential.

pressure means whereby said memb are angularly adactuated by oscillatorymovement .of said actuating ring, and meansv for tilting saidactuatingsring and said oscillating member relativeto saiddrivingfmember on said drive shaft, said tilting means including adiaphragm sensitive to a differential pressure, said diiferentialpressure being directly proportional to the second power of the air masspassing throughthe; intake of said engine, said oscillating memberexerting a component of centrifugal iusted relative to said drive shaftin direct proportion to I V the load on said engine means.

2.'A vacuum controlled variable pressure pump having a tiltableactuating ring and reciprocable pistons driven by said ring, a drive forsaid ring, a chamber formed in one end of said pump for having adiaphragm extending therethrough, one side of said diaphragm beingsensitive to vacuum proportional to the second power of a loadcharacteristic of said ring drive, connecting means interconnecting saiddiaphragm and said ring, said ring drive exerting a component ofcentrifugal force on said ring acting opposite to the force of saidvacuum on said diaphragm transmitted through said connecting means tosaid ring whereby said ring is tilted in direct proportion to the load'on said drive.

3. A wobble plate fluid pump having a drive shaft, an

force proportional to the second power of the speed of said driveshafton said-actuatingring in opposition to the force of saiddifierentialpressure exerted on said it diaphragm References Cited inthe file of this patent UNITED f stares PATENTS

